
#include <cassert>
#include <iostream>

using namespace std;

/**
 * @brief
 *
 * dxj@ubu:~/cpp/test/gcc$ g++ macro.cpp
 * dxj@ubu:~/cpp/test/gcc$ ./a.out
 * HELLO not define
 * dxj@ubu:~/cpp/test/gcc$ g++ -DHELLO macro.cpp
 * dxj@ubu:~/cpp/test/gcc$ ./a.out
 * HELLO defined
 *
 * @return int
 */

int main() {
#ifdef HELLO
  printf("HELLO defined\n");
#else
  printf("HELLO not define\n");
#endif

  cout << (1 << 2) << endl;
  return 0;
}